This invention relates to a valve coupler with decompression.
Thus, the invention relates to a valve coupler of the type which includes an outer tubular body, equipped at one end with rigid connection means to a source of fluid under pressure, to the other end of which is brought the female fitting of the coupler, and this female fitting, which contains the valve situated on the feed circuit side, being designed to permit the engagement and locking, in its bore, of the male fitting of this coupler which, in turn, contains the valve situated on the user side of the fluid under pressure.
In the connection of the male fitting into the female fitting of such a coupler, it is necessary to prevent the valve situated on the user side, that is, in the male fitting, from opening before that situated on the feed side, namely, in the female fitting. This purpose is usually attained because, generally, there prevails in the user circuit, a residual pressure which assists the return spring of the valve of the male fitting, to maintain it in a closed position. However, this advantage is cancelled if there prevails, in the feed circuit, a residual pressure greater than that of the user circuit, since, in this case, the valve of the user circuit will be opened before that of the feed circuit.
There is known from French patent application No. 69 41086 (Pat. No. 2,024,539), a coupler of this type in which, with the valve of the female element situated on the feed side, is associated an auxiliary valve designed to be opened before the main valves, situated on the feed side and the user side, respectively. This device, by causing a fall of the residual pressure possibly prevailing in the feed circuit, has for its purpose the assuring of the opening of the main valve situated on the feed side before that of the main valve situated on the user side.
To obtain the opening of the auxiliary valve before that of the main valves in the coupler according to this French Patent, the return spring, in the closing position of the auxiliary valve, is chosen stronger than those of the main valves, which are both supposed to be assisted by the high residual pressure which ma prevail upstream of each of them.
The return spring of the auxiliary valve, which is necessarily stronger than those of the main valves, and which must be lodged inside a bore of the main valve situated on the feed side, imposes on this latter a great dimension, and thus, considerably increases the cost of manufacture of this coupler.
Moreover, to engage the male fitting, bearing the main valve, situated on the user side, in the female fitting, if a high residual pressure prevails on the feed side, it is necessary to overcome the force of the return spring, which does not facilitate this engagement.